The subject invention relates to resealable containers and resealable closure seals for containers or the like. The invention relates particularly to a multilayer seal for resealing a container such as a bag wherein at least a portion of said seal is permanently adherable to said bag.
Resealable closures for containers are well known in the art. Typically such closures employ a perforated non-resealable closure and a pressure sensitive adhesive strip disposed near the opening of a container such as a bag wherein said non-resealable closure is manually opened and said pressure sensitive adhesive strip serves as the resealable closure. One such resealable closure is disclosed in U.S. Pat. No. 4,902,142, incorporated herein by reference, which discloses an adhesive tape for the reclosable closure of a tubular bag or the like comprising a base layer having two longitudinal adhesive regions separated by a nonadhesive region having a lateral tab for tearing in the longitudinal direction, wherein one of the adhesive regions is disposed over a perforation in the bag to be sealed. Another example of such a closure is disclosed in U.S. Pat. No. 4,786,190, incorporated herein by reference, which discloses a bag having a non-reclosable closure such as a peel seal or a tear line located inwardly of a reclosable closure formed of a pressure sensitive adhesive. U.S. Pat. No. 3,154,239 discloses a resealable bag comprising a saddle-type label having a portion thereof permanently adhered to one side of a non-reclosable bag and having a pressure sensitive adhesive disposed on another portion of said label for reclosably sealing the bag. U.S. Pat. No. 2,991,001 discloses a resealable bag having a tear strip covering an adhesive strip inside said bag for resealing said bag after the non-reclosable seal is opened.
However, the resealable closures of the prior art have several drawbacks. One of the chief shortcomings of the prior art is that the non-resealable closure is formed on the container or package itself, resulting in frequent instances of tearing of the container or package. For example, if the weakened or perforated area provided for the non-resealable closure is not weakened sufficiently, a tear may occur in the container or package itself rather than at the weakened area. It is not a solution to provide excessive weakening in a package such as a bag to avoid damage to the bag during opening, since excessive weakening of the bag results in a non-resealable closure insufficient to prevent premature opening. Nor is it a solution to provide a weak seal which can fracture and permit gas or moisture exchange because the seal no longer acts as a barrier.
In the present invention a foldable closure is provided which is adherable over a container opening wherein the closure comprises a face layer which may comprise polymer, paper, foil or a composite or laminate thereof, said face layer having a front side and a back side, a base layer which may comprise polymer, paper, foil or a composite or laminate thereof, said base layer having a front side and a back side, a releasable and resealable coating or coextruded layer disposed on at least a portion of said back side of said face layer and having an affinity for and adhered to said front side of said base layer, and an adherable coating or coextruded layer disposed on at least a portion of the back side of said base layer. The closure may include a perforation formed in the longitudinal direction to facilitate folding of the closure. The closure seal is folded longitudinally, such as along said perforation, over the opening of a container such that said adherable coating or coextruded layer is at least partially permanently adhered to said container to seal the container. The base layer may include a score cut which allows at least a portion of said base layer to be partially removed from said face layer. If the base layer is score cut the container will be unsealed as removal of the face layer reaches the base layer score cut. If the base layer is perforated, the container is opened by exerting manual pressure on said perforation. In either case, the closure is resealable by pressing said face layer onto said base layer, or alternatively, onto said container if the base layer is removed such as in the form of a coupon. The advantage of using a perforation is that the perforation may be employed to provide a tamper-evident seal. A combination perforation and score cut may be employed to perforate through both layers for ease of folding and score cutting through the base layer only for ease of opening.
The multi-layer construction of the present invention solves the problems associated with the prior art approach of forming a non-resealable closure from the container itself. The base layer of the closure adhered to the container may effectuate the original sealing of the container and the score cut or perforation disposed on the base layer of the closure seal facilitates opening of the container without risk of tearing the container itself. Moreover, the base layer permanently adhered to the container serves to reinforce the container in the area of the container opening. In the case where the base layer is only partially adhered to the container a portion of the base layer may be removed as a coupon and the face layer sealable directly to the container. Optionally, the use of a cling layer prevents adherence of foreign matter such as dust, dirt and food particles that could inhibit resealing. The closure seal of the present invention may be used to seal containers of various construction and composition, including but not limited to bags, packages, boxes and the like comprising coated paper, synthetic paper, plastic, foil, coated film or the like.
It is therefore an object of the present invention to provide a multilayer resealable closure seal comprising a base layer and a face layer, said face layer removably adhered to said base layer, wherein said base layer of the seal is preferably at least partially permanently adhered to the container to be sealed, by positioning said closure seal over the opening of a container, with greater adhesion of the base layer to the container to be sealed than adhesion of the face layer to the base layer so that the face layer can be removed from the base layer with the base layer remaining adhered to the container and said closure is resealable by reapplying said face layer over said base layer.
It is another object of the invention to provide a resealable container comprising the aforementioned resealable closure and the container to be sealed.
It is another object of the invention to provide a resealable closure for a container wherein the resealable closure provides reinforcement of the container to be sealed in the area of the container opening.
It is yet another object of the invention to provide a resealable closure for a container wherein said resealable closure comprises a perforated base layer providing a non-resealable closure and face layer providing a resealable closure.
It is still another object of the invention to provide a resealable closure for a container having a tamper-evident seal.
It is still another object of the invention to provide a resealable closure for a container wherein at least a portion of said base layer is removable in the form of a coupon or the like.
Accordingly, the present invention comprises a foldable multilayer resealable container closure comprising a base layer at least partially releasably adhered to a face layer, wherein said base layer is preferably at least partially permanently adherable to the container to be sealed, and wherein said base layer further comprises a longitudinal perforation for folding the closure over a container opening, and wherein said base layer may further comprise a score cut to facilitate removal of said base layer from said face layer, and wherein said face layer is foldable over said base layer after initial partial removal to reseal said bag. In another embodiment said perforation forms a non-resealable closure which is openable by exerting manual stress on said perforation. In still another embodiment a portion of said base layer is removable such as in the form of a coupon, and the face layer is resealable to the container to be sealed.